Hull down over the Lake Erie horizon from the lush farmland of the Ontario shore, the drilling ship Simcoe sails on venturesome voyages of discovery. Making ready for the coming summer season, her crew of gas-exploring seamen keep weather eyes open as they prepare to sink their drills down through Erie's shallow but easily-aroused waters. Last year, as Canada's total natural gas production zoomed 44 per cent to 2.6 billion cubic feet per day, Lake Erie gas drillers put down 47 new holes into the 400-million-year-old Silurian Sea deposits a thousand feet beneath the lake bed. While these operations are but a fraction (less than three per cent compared to Alberta's nearly 80 per cent) of Canada's overall, thriving gas industry, Ontario gas production is economically very important. Close to heavily-industrialized, densely-populated areas, the gas from southern Ontario has a value four times that of gas from more remote regions. Gas from the new wells will replace present provincial daily imports of 14 million cubic feet from the U.S., due to terminate in 1967. Today, with Canada exporting in return a billion cubic feet per day, the nation's estimated recoverable reserves are counted in the tens of thousands of billions. This year the converted freighter Simcoe, in her third season of off-shore drilling, will add more wells to the 200 already in production in Lake Erie, will add to the significant shoreward flow of gas through a 15-mile underwater gathering system, play a major role in bringing the long-hidden energy under Lake Erie to the heart of Canada's industrial south.